Solution Structure of a Natural CPPC Active Site Variant, the Reduced Form of Thioredoxin h1 from Poplar

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• 作者：Nicolas Coudevylle ; Auré ; lien Thureau ; Christine Hemmerlin ; Eric Gelhaye ; Jean-Pierre Jacquot ; and Manh-Thong Cung
• 刊名：Biochemistry
• 出版年：2005
• 出版时间：February 15, 2005
• 年：2005
• 卷：44
• 期：6
• 页码：2001 - 2008
• 全文大小：404K
• 年卷期：v.44,no.6(February 15, 2005)
• ISSN：1520-4995

文摘

Assignment of heteronuclear and homonuclear multidimensional NMR spectra permitsdetermination of the first three-dimensional solution structure of a higher-plant thioredoxin h. The collectionof 1906 distance restraints, 137 TALOS-derived dihedral restraints, and 66 hydrogen bonds was used inthe restrained molecular dynamics protocol to calculate the structure of the reduced form of thioredoxinh1 from poplar with an atomic rmsd of 0.60 ± 0.12 Å. This enzyme exhibits an unusual active site withthe sequence WCPPC and original properties in terms of stability and specificity. Compared to otherknown thioredoxin structures, thioredoxin h1 from poplar adopts the classical "Trx fold". Its atypicalactive site possesses a conformation similar to that of other common thioredoxins but appears to be morerigid. Moreover, the hydrogen bond network, stabilizing the in-core -sheet, is tighter than inChlamydomonas reinhardtii, explaining the difference in thermostability.